Common video slot machines randomly select and display an array of symbols using virtual reels, then grant an award to a player based on the occurrence of certain symbol combinations across paylines. All symbols in a column are located on a single reel. Such reels limit the possibilities of game features, since the symbols in a column all move together.
Video slot machines are known that display a matrix of reels, where each reel ultimately only displays one symbol. One such machine is described in U.S. Pat. No. 5,393,061, incorporated herein by reference. These types of machines have generally just been used to play the same basic game as a standard video slot machine with the large vertical reels.
Typically, the game ends after a single spin of the reels and any award is granted. Although these types of basic games are highly successful, it is advantageous to provide special features that occur once in a while to make the game more interesting to a player. A more interesting game will generate increased revenue to the casino by increased play of the gaming machine.